Closure For A Container

ABSTRACT

A closure for a container having a circular opening defining an axis, the closure being securable to the container so as to close said opening, the closure having an o-ring sealing member mounted thereon so as to provide a seal with a sealing surface of the container, when the closure is secured to the container, the sealing surface extending around an upper surface or an internal surface of the container. The closure may comprise a bore feature which, in use, extends through the opening into the interior of the container and the o-ring seal may be provided on the bore feature. Various forms of closure are described, e.g. for closing a bottle neck and a wide-mouth closure. The closure may comprise an inner component and an outer component, e.g. a cap-on-collar closure, and the container preferably has no thread features on the exterior thereof so it is comfortable to drink from.

TECHNICAL FIELD

This invention relates to a closure for a container, in particular aclosure for a beverage or other foodstuff (although the closure can beused on other types of container).

BACKGROUND ART

A variety of closures for beverage containers are known. For example,cap-on-collar closures as described in WO2006/000774 and WO2007/091068and one-piece twist-off closures as described in WO2007/057659. Suchprior art describes a variety of seal members, such as compressiongaskets, for providing a seal between the closure and the container.

There is a requirement to provide a seal which is able to withstand highpressures within the container, eg when the container holds a carbonatedbeverage and is subject to high temperatures, yet which does not make itdifficult for a user to remove the closure from the container. A varietyof problems can arise with such seals, for example: high frictionalengagement between the seal and the container, (particularly forwide-mouth containers), seals losing their resilience and/or becomingadhered to the container after prolonged storage and imperfections inthe seal or the container (particularly if a glass container is used)leading to weak points in the seal.

The present invention provides an alternative form of seal for suchclosures which seeks to reduce or overcome one or more of the problemsexperienced with the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided aclosure for a container having a substantially circular opening definingan axis, the closure being securable to the container so as to closesaid opening, the closure having an o-ring sealing member mounted ormountable thereon so as to provide a seal with a sealing surface of thecontainer, said sealing surface extending around an upper surface or aninternal surface of the container.

It should be noted that the term o-ring seal as used herein is to beunderstood to include a seal comprising a toroid or loop of elastomermaterial having a circular cross-section, as well as othercross-sections, including an oval cross-section, a substantially squarecross-section and a x-shaped cross-section (sometimes referred to as anx-ring). It is also to be understood to cover other forms of seal whichsimulate the function of an o-ring (as described further below).

In addition to the elastomer toroid, an o-ring seal comprises a groove(referred to as a gland) in which the toroid is located. This groovetypically has a substantially square cross-section but other shapes canbe used, including triangular and semi-circular. The groove provideslocating means for locating the o-ring and at least one side wall. Theside wall is located so that when one side of the o-ring is subject toelevated pressure, the o-ring is pressed against the side wall so as toseal a gap between the side wall and the sealing surface of thecontainer body. For a container in which the internal pressure isreduced, eg a vacuum pack, the side wall is on the inner side of theo-ring and for a container in which the internal pressure is elevated,the side wall is on the external side of the o-ring. If a side wall isprovide on both sides of the o-ring, it can provide a sealing functionin both circumstances.

The invention also relates to a closure as described above incombination with a container adapted to be closed by said closure.

The invention is particularly applicable to widemouth closures (eg witha diameter of 50 to 80 mm) as the larger the opening the more difficultit is to provide an effective and reliable seal between the closure andthe container whilst ensuring the closure is still relatively easy toremove. However, the invention is also applicable to narrower openings,eg of a bottle such as those having a 28 mm diameter opening.

Directional terms, such as upper and lower, as used herein are to beunderstood to refer to refer to directions relative to a containerstanding on a horizontal surface with the axis passing through itsopening being substantially vertical (unless the context clearlyrequires otherwise).

Preferred and optional features of the invention will be apparent fromthe following description and from the subsidiary claims of thespecification.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be further described, merely by way of example,with reference to the accompany drawings, in which:

FIG. 1 is a part cross-sectional view of a first embodiment of a closureaccording to the present invention when fitted to a container body;

FIG. 2 is a part cross-sectional view of a second embodiment of aclosure according to the present invention when fitted to a containerbody;

FIG. 3 is a part cross-sectional view of a third embodiment of a closureaccording to the present invention when fitted to a container body;

FIG. 4A is a perspective view of a fourth embodiment of a closureaccording to the present invention and of a container body to which itcan be fitted;

FIG. 4B is a perspective view, part cut-away, of the fourth embodimentwhen fitted to the container;

FIG. 5A is a perspective view, part-cut-away, of a fifth embodiment of aclosure according to the present invention when fitted to a containerbody;

FIG. 5B is a perspective view, part-cut-away, of a modified version ofthe fifth embodiment using a different form of o-ring;

FIG. 6A is a perspective view, part-cut-away, of a sixth embodiment of aclosure according to the present invention when fitted to a containerbody;

FIG. 6B is a perspective view, part-cut-away, of a modified version ofthe sixth embodiment using a different form of o-ring;

FIGS. 7A to 7C are schematic diagrams illustrating the function andparameters of an o-ring seal.

FIGS. 8 and 9 are cross-sectional views of an embodiment of a closuredescribed in co-pending GB1011800.8 which, as described therein, may bemodified to include a bore feature and an o-ring in accordance with afurther embodiment of the present invention; FIG. 8 shows the partsthereof prior to securement to a bottle neck and FIG. 9 shows the partswhen the closure has been moved into secure engagement with the bottleneck;

FIGS. 10A and 10B show a side view and a cross-sectional view (taken online E-E of FIG. 10A) of an inner component of the closure shown inFIGS. 8 and 9;

FIGS. 11A and 11B show perspective views from above and beneath of theinner component of FIG. 10;

FIGS. 12A and 12B show a side view and a view from beneath of an outercomponent of the closure shown in FIGS. 8 and 9; and

FIGS. 13A and 13B show perspective views from above and beneath of theouter component of FIG. 12.

The embodiments shown in FIGS. 1 to 3 comprise cap-on-collar closures.This type of closure is known from prior art, such as WO2006/000774 andWO2007/091068 mentioned above, so will not be described in detail.

FIG. 1 illustrates an embodiment that comprises a closure for acontainer body 1 having a substantially circular opening with an axis Aand with an outwardly projecting lip 1A around the opening. The closurecomprises a cap 2 to close the opening and a collar 3, the collar 3being arranged to engage beneath the outwardly projecting lip 1A and tofit between the container body 1 and the cap 2 so as to secure the cap 2to the container body 1 in the manner described in the prior art. Thecap, collar and container are typically formed of a plastics material egpolyethylene terphthalate (PET) but may be formed of other materials.The container may, for instance, be formed of glass and the closureformed of metal.

The cap 2 has a circular upper portion which extends across thecontainer opening and a skirt portion 2B depending therefrom. The capalso has a bore member 4 which, in use, extends through the opening intothe interior of the container 1 and has an o-ring sealing member 5 onthe outer surface of the bore member 4 for providing a seal with aninternal surface 1B of the container.

The bore member 4 may be an integral part of the cap 2 or, as shown, maybe a separate component carried by the cap 2 and is arranged to be aclose fit within the interior of the container 1 (but slightly spacedtherefrom). A recess, eg in the form of a groove 4A, is provided in theouter surface of the bore member around the circumference thereof forreceiving an o-ring 5 formed of resilient elastomer material, such asrubber.

The cap 2 is rotatable relative to the collar 3, eg by means of a screwthread therebetween. The collar 3 has radially moveable parts 3B whichengage beneath the lip 1A of the container body 1 and as the cap isrotated in the tightening direction it is arranged to press the partsinward under the lip 1A and to hold them securely in this position, egby means of cam features at spaced apart locations around the internalsurface of the cap. Alternatively, the moveable parts may be biasedinwards by their own resilience and the cap 2 rotated to a position inwhich it holds the parts securely beneath the lip 1A by preventing themfrom moving or flexing radially outwards.

Preferably, as the cap 2 is rotated in the tightening direction relativeto the collar 3, the cap 2 is drawn axially downwards towards an uppersurface 1C of the lip 1A. It may engage this upper surface 1C when inthe closed position or, as shown (in an exaggerated form) in FIG. 1, maybe spaced therefrom to reduce the risk of becoming adhered thereto overtime. If it is spaced therefrom, the spacing is preferably relativelysmall, eg less than 0.5 mm so as to minimise the scope for verticalmovement of the closure relative to the container body when in thesealed position.

In a further arrangement (not shown), the cap 2 may engage the uppersurface 1C of the lip directly or via a secondary sealing member 6therebetween to provide a secondary seal between the cap 2 and thecontainer body 1.

As indicated above, when the closure is mounted on the container body 1,the bore member 4 extends into the interior of the container body 1 andthe sealing member 5 is a close fit with the internal surface 1B of thecontainer body. As the cap 2 is rotated relative to the collar 3 in thetightening direction, the bore member 4 is drawn further into thecontainer body 1 and the o-ring provides a seal between the bore member4 and the interior of the container body 1.

The inner edge of the container lip is preferably chamfered so as toprovide a lead-in surface for the o-ring 5. The o-ring 5 then engages aportion 1B of the internal surface of the container body which comprisesa substantially parallel sided cylindrical surface. The function of ano-ring 5 will be described further below in relation to FIGS. 7A and 7B.The cylindrical surface 1B extends axially for a distance (typicallyseveral millimetres), sufficient to accommodate axial movement (up ordown) of the bore member 4, eg due to pressure differentials between theinterior and exterior of the container. As this surface 1B is parallelsided, such movement can be accommodated without affecting the sealbetween the closure and the container body.

It will be seen that the groove 4A within the bore member 4 isthree-sided and, together with said internal surface 1B of the containerbody, defines a four-sided enclosure for constraining the cross-sectionof the o-ring 5. The side walls of the groove 4A are preferablysubstantially perpendicular to the sealing surface 1B. As will bedescribed further below, the enclosure only needs to be 3-sided, ie twosided (eg L-shaped or V-shaped groove) together with the sealing surfaceof the container.

A shoulder 1D is optionally provided beneath the cylindrical surface 1Bof the internal wall of the container leading to a reduced diameterportion 1E of the container wall. Beneath this, the container wall mayhave any desired shape. The reduced diameter portion 1E is provided sothat automatic handling tools, eg in a filling line, can grip theinterior of the container without damaging the cylindrical sealingsurface.

The shoulder 1D may also provide a stop feature for limiting themovement of the bore feature into the container.

It will be appreciated that in arrangements in which the thread form hasan inclined portion rotation of the cap relative to the collar isconverted into axial movement of the o-ring within the container and soprovides a significant mechanical advantage in effecting this movement.In addition, compression of the o-ring is primarily in the horizontaldirection so does not resist axial movement of the ring. This greatlyreduces the torque required to tighten the closure.

As indicated above, the bore member 4 may be integrally formed with thecap 2 or may be a separate component. In the latter case, there are moreoptions for forming the bore member 4 from a material, eg a metal,different to that from which the cap 2 is formed. A metal bore member isadvantageous as it is generally impermeable to gas. If a plastics boremember is used, it is preferably formed of a plastic material which hasbeen modified to reduce its gas permeability. A metal bore member alsohas the advantage that it expands as the temperature increases and thusfurther compresses/deforms the o-ring seal to enhance the seal with thecontainer.

A separate bore member 4 may be mounted to the underside of the cap 2 ina variety of ways, eg by being adhered or welded thereto or by simplybeing clipped therein (as shown in FIG. 1). The engaging portions of thecap and bore feature are preferably provided at localised areas aroundthe circumference to reduce the frictional engagement therebetween (thebenefit of which is discussed below). The cross-section shown in FIG. 1is through one of these locations.

The bore member 4 may be arranged such that the cap 2 is rotatablerelative to the bore member 4 so, once the o-ring 5 has frictionallyengaged the sealing surface 1B, the bore member 4 no longer rotatesrelative to the container body 1 as the cap 2 is rotated furtherrelative to the collar 3. Instead, if the frictional engagement betweenthe bore member 4 and the container body 1 is greater than that betweenthe bore member 4 and the cap 2, the bore member 4 merely moves axiallywithin the container body 1. This means that the o-ring 5 also only hasto move axially within the container, rather than rotating relativethereto, as the cap is tightened or loosened on the collar 3, and sogreatly reducing the torque required to tighten or loosen the closure.In such an arrangement, rotation of the cap thus serves to drive thebore member (and o-ring) axially further into the container. In othercases, this need not be the case.

FIG. 2 shows a closure which is similar to that of FIG. 1 (withcorresponding parts having reference numbers increased by 10) exceptthat the bore member 14 is integrally formed with the cap 12 and theupper portion 12A of the cap has an annular form (rather than beingcircular and extending across the container opening). In this case, itis just the bore member 14 that extends across and closes the containeropening.

This embodiment has the advantage of simplicity as it comprises fewercomponents. The recess 12C in the closure can also provide a locationfor a promotional item (not shown).

FIG. 3 shows a third embodiment similar to that of FIG. 1 (withcorresponding parts having reference numbers increased by 20) but inthis case, the o-ring sealing member is part of a resilient member 25fitted to the underside of the bore member. The resilient member 25 ismoulded to fit the underside of the bore member 24 and has a portion 25Awhich simulates a toroidal o-ring. This portion 25A has an approximatelycircular cross-section, eg square with rounded corners as shown in FIG.3, and is located in a groove 24A which extends around the circumferenceof the bore member 24. As shown, this groove 24A comprises an upper faceand a rear face and these faces, together with the cylindrical face 21Bof the container body, constrain the cross-section of said part 25A, atleast when subject to an elevated pressure within the container 21 (NBthis embodiment would not be suitable to for use in applications inwhich the pressure in the container is reduced, ie in a vacuum pack, asthe groove does not have a lower face to constrain said part againstmovement into the container).

FIGS. 4 and 5 show embodiments in which the closure is secured directlyto the container, eg by means of a thread on the exterior of thecontainer, ie without the need for a collar. These embodiments alsoemploy an o-ring to provide a seal between the closure and the containerand many features correspond to those described above (and are givensimilar reference numbers but increased by 30 or 40).

FIGS. 4A and 4B show a fourth embodiment with a one piece closure thatis rotatably secured to the container by means of a threaded engagementtherebetween. The closure comprises a cap 32 with a circular portion 32Athat closes the mouth of the container 31 and a skirt portion 32B. Theskirt portion 32B has thread features 32C at spaced apart positionsaround its circumference which engage with thread features 31A spacedaround the exterior of the container lip 31B. As shown in FIG. 4B, thecircular portion 32A is part of a bore member 34 that extends into thecontainer 31 and an o-ring seal 35 is provided in a groove 34A in theexterior of the bore member 34. The o-ring seal 35 engages a sealingsurface 31C around the inner circumference of the container 31.Preferably, this surface 31C is substantially cylindrical (as discussedabove) but, as shown in FIG. 4B, may also be part of a surface thatreduces in diameter towards the mouth of the container 31. With thisarrangement, an elevated pressure within the container 31 urges the cap32 upwards so the o-ring 35 engages a sealing surface 31C of reduceddiameter so the sealing engagement therewith is increased.

The cap 32 shown in FIG. 4 may be made from metal and the threadfeatures 32C thereof formed by a pressing operation. As shown, thethread form is preferably a multi-start thread form, in this case aneight-start thread form that requires a rotation of only about 45degrees to fasten or release the closure.

FIG. 5A shows a fifth embodiment of a closure. This is similar to theone-piece closure of FIG. 4 except that the o-ring 45 is mounted in agroove which is positioned on the bore feature 44 such that the sealingsurface 41C that the o-ring engages is a conical surface of thecontainer 41. In the example shown, this conical surface 41C lies at anangle of substantially 45 degrees with the axis A and comprises thechamfer which extends from an upper surface of the container lip intothe interior of the container 41. The conical surface 41C may lie atother angles to the axis A depending upon the application, the natureand magnitude of the internal pressures and the hardness of the o-ringmaterial 45.

This embodiment has the advantage that the cap 42, and particularly thegroove used to housing the o-ring, is easier to form by a pressingoperation than the arrangement shown in FIG. 4.

Also, as the sealing surface 41C has a vertical component, the o-ringmoves down this surface as the cap 42 is tightened onto the container41. This reduces the force required to tighten the closure (compared toan arrangement in which the sealing surface is perpendicular to the axisA) as this force moves the o-ring downwards as well as compressing thering. As the sealing surface is inwardly inclined, it also serves tocompress the o-ring in the horizontal direction.

FIG. 5B shows a modified form of the fifth embodiment in which an o-ringseal 45′ having a cruciform cross-section (sometimes referred to as anx-ring) is used in place of an o-ring with a circular cross-section.This form of o-ring has the advantage that it seals at four pointsrather than two.

FIG. 6A shows a sixth embodiment of a closure. This is similar to theone-piece closure of FIG. 4 except that the o-ring 35 is mounted in agroove which is positioned so that the sealing surface that the o-ringengages is an upper surface of the container lip. Preferably, as shown,the cap still has a bore member that extends into the interior of thecontainer. In the arrangement shown, the sealing surface is a radiallyinner portion of the upper surface which abuts the internal surface ofthe container. If the interior of the container is subject to reducedpressure, eg in a vacuum container, the o-ring is thus pressed into thegap between the bore member and the inner rim of the container. The sealthus formed may thus be regarded as being formed with the interiorsurface of the container if the corner where this meets the uppersurface is included as part of the interior surface.

FIG. 6B shows a modified form of the sixth embodiment in which an o-ringseal 55′ having a cruciform cross-section (sometimes referred to as anx-ring) is used in place of an o-ring with a circular cross-section. Asindicated above, this form of o-ring has the advantage that it seals atfour points rather than two.

In a further modification (not shown) of the sixth embodiment, the uppersurface of the container lip may be shaped so that the sealing surfacethat the o-ring engages is not the uppermost surface of the lip. Thissealing surface may be provided on the inner side of the lip, in whichcase the bore feature and the o-ring carried thereby extend through theopening of the container into the interior of the container (in asimilar manner to that shown in FIG. 5).

Alternatively, the sealing surface may be around the exterior of theupper surface of the container lip, eg in the form of a recess orchamfer about the external diameter of the lip. As indicated above, ifthe sealing surface is inclined (so as to have a vertical component),the torque required to tighten the closure is reduced as the forcesapplied to compress the o-ring are at an angle to the axis A so are notdirectly opposed to the vertical movement (along axis A) of the closure.

Thus, in these modifications, the sealing surface is an upper surface ofthe container lip (or an internal surface of the container) but notnecessarily the uppermost surface of the lip.

Preferably, as will be seen that in each of these embodiments, the sidewalls of the groove housing the o-ring are substantially perpendicularto the sealing surface of the container.

FIGS. 7A to 7C illustrate the function and parameters of an o-ring seal.FIG. 7A shows a cross-section of an o-ring 75 with a circularcross-section in an undeformed state. The cross-section has a diameteror width CS. FIG. 7B shows the o-ring 75 located in a groove or gland74A having a depth D and compressed between the rear sealing face 748 ofthe groove and an external sealing face 71B (such as the internalsurface of the container body). In this case, the o-ring 75 is subjectto equal pressures on either side thereof (left and right in FIG. 7B).

An o-ring has an inner and outer diameter and a cross-sectional diameterCS (which is the difference between the inner and outer diameters). Theouter diameter is determined by the diameter of the container opening(and is typically slightly greater than the diameter of the containeropening). The cross-sectional diameter CS will depend upon theapplication but for containers having a diameter in the range 50-80 mmwill preferably be in the range of 2.0-3.0 mm. For narrower mouthcontainers, eg with a 28 mm diameter opening, CS will preferably be inthe range 1.0-2.0 mm. It should be noted that CS refers to thecross-section of the uncompressed o-ring when mounted in the groove. Ifthe ring is stretched when located in the groove this cross-section willbe smaller than the cross-section in an unstretched condition.

O-rings are typically formed of elastomers. Elastomers may be syntheticor natural resilient materials with sufficient memory to return to theiroriginal shape after a major or minor distortion. The resilience is whatenables an o-ring to provide a seal and the parameters of the seal andthe gland are selected to make effective use of this.

The o-ring is positioned in an enclosed space which both compresses andlocates the o-ring. The containment ensures that the sealing function ismaintained and the o-ring retained in the desired position. The enclosedspace is formed by the walls of the groove or gland and a sealingsurface facing the open side of the groove or gland. FIG. 7B illustratesan enclosed space having a height H and a width W. The gland is formedin a relatively rigid material (and thus from a different material fromthe o-ring). The o-ring positioned in this space is compressed so itscross-sectional width is reduced from CS (shown in FIG. 7A) to H.

The term ‘compressed’ is used herein to describe this change of shape.However, it should be noted that elastomers are substantiallyincompressible so the term ‘deformation’ is technically more accurate.The cross-sectional area of the o-ring in the ‘compressed’ state is thussubstantially the same as it is in the uncompressed state.

The opposing surfaces 71B and 74B of the gland are sealing surface andtheir spacing H is less than the o-ring cross-section CS so the o-ringis compressed as shown resulting in sealing forces between the o-ringand each of the surfaces 71B and 74B.

The opposing surfaces 74A and 74C are containing surfaces and thedistance W between them is equal to or larger than the diameter CS ofthe o-ring. The primary function of these surfaces is to keep the o-ringin place.

Two of the most important parameters that affect the performance of ano-ring seal are the compression squeeze and the compression ratio. Thecompression squeeze is defined as;

Compression squeeze=CS−H

And the compression ratio expresses what percentage the compressionsqueeze is of the uncompressed o-ring cross-section:

Compression ratio=(compression squeeze/CS)×100

The compression squeeze should have a minimum value of 0.1 mm and ispreferably at least 0.15 mm.

The compression ratio should be in the range 5% to 35% and preferably inthe range 20% to 25%.

Another parameter of an o-ring seal is the extrusion gap G which is theheight of the spacing between the sealing surface 71B and the outersurface of the bore member (or other component) adjacent the opening ofthe groove formed therein. The gap G is the difference between thedimensions H and D: so G=H−D.

The gap G should be significantly smaller than the cross-section CS ofthe o-ring, eg no greater than 20% of CS and preferably no greater than10% of GS. In most cases, the gap G is very small, eg 0.5 mm or less andpreferably 0.25 mm or less. However, in some cases, the gap may beslightly larger due to manufacturing tolerances in the formation of thecontainer and the bore member of the closure, or due to specificdesigns, such as food applications, whether it may be desirable for theo-ring to be allowed to extrude partially into the gap.

If the gap G is very small, this means that the depth D of the gland isthus preferably 65%-95% of the o-ring cross section CS and preferably75% to 80% of the cross-section CS.

In cases where the gap G is larger, the depth D of the gland shouldstill be at least 50% and preferably at least 60% of the cross-sectionCS.

Another important parameter of an o-ring seal is gland fill. This is thepercentage of the gland that is occupied by the o-ring. Thecross-section area (CSA) of a circular o-ring is pi×(CS/2)² and thegland cross-sectional area (CSA) is H×W. Thus, the gland fill is givenby:

(o-ring CSA/gland CSA)×100

The gland fill should lie in the range 50% to 90% and preferably in therange 65% to 85%.

FIG. 7C illustrates how the o-ring 75 moves within the groove 74A and isdeformed when subject to pressure P from one side (the right side ofFIG. 7C). The o-ring 75 moves within the groove 74A away from the higherpressure P and is pressed against the side face 74C at the other side ofthe groove 74A. It is deformed so as to seal the gap 76 between thecomponent housing the groove 74A and the face 71B. Given the nature ofthe o-ring (and the size of the gap), deformation of the o-ring intothis gap is usually minimal. It will also be seen that a substantialproportion (greater than 50%) of the o-ring surface is engaged with asurface (71B, 74B, 74C) of the gland so as to provide a seal therewith.

The parameters described above have been described in relation to aconventional o-ring with a circular cross-section. However, similarparameters apply to other variants of a o-ring, eg when the o-ring hasother cross-sectional shapes and/or when the gland has other forms (eg a3-sided gland as shown in FIG. 3, or an L-shaped or V-shaped glandformed by two inclined side walls) with the appropriate dimensions usedin place of those illustrated in FIG. 7. It will be appreciated thatwhen the o-ring is subject to a pressure differential acting to move itin one direction, the gland only need have one side wall, eg so thegroove is L-shaped.

The function of o-ring seals, and their technical parameters, arefurther described in the Dichtomatik O-Ring Handbook published byDichtomatik North America (and available in 2010 on their web site athttp://www.dichtomatik.us/Literature/O-ring-Handbook.aspx)

It will be appreciated that the sealing action of an o-ring is verydifferent to that of known beverage container seals such as a sealinggasket which is trapped between two flat surfaces, a seal with one ormore flexible sealing fins or a wedge seal trapped in a tapering gapbetween a plug member and a container bore. The principal sealingsurfaces of an o-ring are the opposing surfaces 71B and 74B betweenwhich the o-ring is compressed and the engagement of the o-ringtherewith.

FIGS. 8 to 13 illustrate a two-part closure as described in co-pendingGB1011800.8. The inner and/or outer component of this two-part closuremay, as described in GB1011800.8, comprise a bore feature (not shown)which projects through the mouth of the container into the interiorthereof and the bore feature may be provided with an o-ring seal whichengages and seals with the interior of the container (or an uppersurface thereof). These further embodiments of the two-part closure thusform further embodiments of the present invention. The two-part closurewill be described with reference to FIGS. 8-13 followed by descriptionof the arrangements (not shown in these Figures) having a bore featureand an o-ring seal.

The closure shown in FIGS. 8-13 comprises an inner component having acollar portion for fitting about the exterior of a container 82, in thiscase a bottle neck having a container opening defining an axis A, andwhich has radially moveable parts 83 spaced around its circumference forengaging beneath a lip 82A of the container 82, and an outer componenthaving a skirt part 84A for locating about the radially moveable parts83 of the inner component.

The outer component 84 is designed to be located over the innercomponent 81 by substantially axial movement therebetween and comprisesone or more cam surfaces 84B on its inner surface which engage the upperends of the radially moveable parts 83 as the components are movedaxially so as to progressively press the parts 83 inwards into tightfrictional engagement with the exterior of the container beneath the lip82A of the container 82. The cam surfaces are thus arranged to holdand/or press an expandable/contractable portion of the inner componentinto secure engagement with the container beneath said lip,

Once the outer component 84 has been moved axially over the innercomponent 81 so as to press the radially moveable parts 83 inwards, itis twisted relative to the inner component 81 about the axis A so as toengage securement means which releasably secure the inner and outercomponents together in this position. In the embodiment shown, thesecurement means comprises substantially upwardly facing surfaces 85A ofinward projections 85 at the lower end of the skirt part 84A of theouter component and substantially downwardly facing surfaces 83A of theradially moveable parts 83. The surfaces 85A and 83A may provide abayonet-form of engagement between the inner and outer components and/ora thread-like engagement therebetween. The surfaces may be shaped orinclined such that said relative rotation between the inner and outercomponents also causes axial movement therebetween.

In the closure shown in FIGS. 8 and 9, the inner component 81 alsocomprises a flexible sealing portion 86 which extends over the openingin the bottle neck, over an upper surface of the container lip andextends down the exterior of the bottle neck. The flexible portion 86 ispreferably integrally formed with the radially moveable parts, e.g. by atwo-shot moulding process. The radially moveable parts are formed of arelatively rigid material, e.g. polyethylene terephthalate (PET), andthe flexible portion of a relatively flexible material e.g. anelastomer. The function of the flexible sealing portion 86 will bedescribed further below.

The outer component 84 comprises a top part from which the skirt partdepends and which extends across the upper surfaces of the lip 82A andacross the container opening.

The inner component 81 will be described in more detail with referenceto FIGS. 10A and 10B. As shown in these figures, the inner componentcomprises two principal parts: a collar portion which comprises a ring83B with a plurality of radially moveable parts 83 upstanding from thering 83B and circumferentially spaced around the ring 83B and a flexiblesealing portion (described further below). Each of the moveable parts 83has a rounded upper end 83C for engagement with the cam surfaces 84Bdescribed above and for engaging the underside of the container lip 82A.Preferably, the upper end 83A of the moveable parts 83 is shaped tosubstantially match the concave profile of the container on theunderside of the lip 82A (as shown in FIG. 9).

The outer face 83D of each of the moveable parts is substantially flatso as to be a snug fit within the skirt 84A of the outer component 84when the closure is in an unsecured position (as shown in FIG. 8). Eachmoveable part 83 also has a lower, substantially downwardly facingsurface 83A as described above. This acts to retain the inner component81 within the outer component 84 in the unsecured position (as shown inFIG. 8) so the inner and outer components can be easily pre-assembled;the inner component 81 being a snap fit within the outer component 84 asthey are brought together in the axial direction, the moveable parts 83flexing as they pass over the inward projections 85 until they snapoutwards so the lower surface 83A of the moveable part engages the uppersurface 85A of the inward projections 85.

In the position shown in FIG. 8, the surfaces 83A and 85A aresubstantially horizontal i.e. perpendicular to axis A. However when theinner and outer components are moved axially relative to each other tothe position shown in FIG. 9, the moveable parts 83 are flexed inward.The lower surface 83A of the moveable part is thus tilted inwards so asto be inclined to the horizontal. Accordingly, the upper surfaces 85Aare preferably shaped so that when the outer component 84 is twisted tothe secured position the surface 85A is similarly inclined to thesurface 83A.

In addition, in many cases, is desirable for the engagement between thesurfaces 83A and 85A, as the outer component 84 is rotated or twistedabout axis A to a second position, for the inner and outer component tobe drawn together axially whereby the outer component 84 is drawn downtowards the upper surface of the container lip 82A and the moveableparts 83 drawn tightly upwards beneath the lip 82A of the container. Thesurfaces 83A, 85A are thus inclined in the circumferential direction inthe manner of a screw thread to effect a tight securement of the closureto the container as the inner and outer components rotated relative toeach other in a tightening or closing direction about axis A. As theouter component is rotated relative to the inner component, the outercomponent is drawn down so as to compress the flexible sealing portionof the inner component against the upper surface of the container lipand the moveable members 83 are pressed upwardly into secure engagementwith the container beneath the container lip.

In the embodiment shown, the ring 83B projects beneath the skirt 84A ofthe outer component so is visible from the exterior (as shown in FIGS. 8and 9). However, in other embodiments, the ring may be concealed by theskirt, at least when in a secured position corresponding to that shownin FIG. 9.

An important feature of the collar portion of the inner component isthat the upper ends of the moveable components that are free to flexradially inwards and outwards, this movement taking place about a pivotat or towards the lower end of the collar (in contrast to a collar whichis located the other way up i.e. with the moveable parts extendingdownwards from a ring portion).

The other principal part of the inner component is the flexible sealingportion 86. In the embodiment shown, this is in the form of a cap withan upper end 86A extending across the upper end of the container 82 andan upper surface of the lip and a skirt portion extending down theoutside of the bottle neck to the ring 83B of the collar.

The flexible portion 86 performs several functions. First, it acts as asealing component in that it is sandwiched between the outer component84 and the upper surface of the lip 82A of the container so as toprovide a gasket seal therebetween. In the arrangement shown, it alsoextends across the mouth of the container and so closes the containeropening. In addition the flexible portion lies between the substantiallyrigid moveable parts 83 and the outer surfaces of the bottle neck andacts as a high friction component between these surfaces.

As indicated, the collar portion and the sealing portion are preferablyintegrally formed. This can be achieved, for example, by a two-shotmoulding technique in which the different materials are consecutivelyinjected so they are integrally bonded or connected to each other. Thisalso has the significant advantage that the closure comprises just twoparts: the inner component and the outer component. In knowncap-on-collar closures, it is usually necessary for the sealingcomponent to be provided separately or secured in some manner to theunderside of the outer component.

The outer component 84 will now be described in more detail withreference to FIGS. 12A and B and FIGS. 13A and B.

In the embodiment shown, the outer component is in the form of a capwith an upper portion 84C which extends over the upper surface of thelip 82A and extends across the opening of the container 82 and has askirt portion 84A depending therefrom.

The skirt portion 84A is provided with inwardly extending projections 85at or toward the lower end thereof. As described above, the uppersurface 85A of each projection 85 is preferably inclinedcircumferentially so it acts as a screw thread and tilts radiallyinwards to an increasing extent along its circumferential length so asto match the inclination of the lower surface 83A of the moveable part83 that it engages. This thread path may extend over two or threeadjacent parts 83.

The closure is designed so that only a relatively small twist isrequired to move it from an unsecured (FIG. 8) position to a secured(FIG. 9) position. In the embodiment shown, a twist of onlyapproximately 60 degrees is required. Accordingly, the inward projection85 comprises six sections around the inner circumference of the skirtportion 84A as shown in FIGS. 12B and 12B.

As indicated above, the outer component engages downwardly facingsurfaces of the radially moveable parts so as to secure and/or tightenthe inner and outer components together in the axial direction. This isan important feature as it enables both the inner and outer componentsto be relatively short in the axial direction so they can be formed toresemble a conventional cap-like closure. This also means that thethreaded engagement between the inner and outer components comprisescircumferentially spaced apart features (the surfaces 83A of therespective parts 83). This enables the threaded engagement therebetweento require only a relatively small rotation or twist (rather thanseveral complete rotations as required by a continuous helical threadform). Furthermore, this provides a very compact and robustconstruction. The upwardly facing surfaces 85A of the outer componentapply an upward force which is directly transmitted via surfaces 83Athrough parts 83 which have a rigid, strut-like form to the underside ofthe lip 82A.

This high friction engagement can also be provided in other ways. Thecollar component may be provided with a lining of high friction material(irrespective of whether this is connected to a sealing component thatpasses over the upper surface of the container lip) or the inner surfaceof the collar component could be provided with a roughened finish whichis sufficient to increase the frictional engagement with the containerto the required level. In another alternative, a high friction sleeve,eg of rubber, could be fitted around the container neck.

In addition, the flexible sealing component extends over the uppersurface of the lip 82A and so provides a sealing member between theclosure and the container. The provision of a single component that actsboth as a collar for fitting around the exterior of the container and asa sealing component between the closure and the container, is asignificant feature of this closure.

As described, when the outer component is moved with respect to theinner component so as to press the moveable parts 83 inwards, thismovement is primarily axial. In other embodiments, this axial movementmay be provided by means of a small twisting movement although it is theaxial component that moves the cams downwards so as to press the parts83 inwards. The twisting movement is preferably less than 360 degreesand more preferably less than 90 degrees or less than 60 degrees. Thisis in contrast to arrangements in which a small axial movement is aconsequence of several complete rotations of the outer componentrelative to the inner component, eg as provided by a continuous helicalthreadpath.

In further embodiments (not shown) of the closure shown in FIGS. 8-13,in particular closures for widemouth containers, the inner and/or outercomponent may comprise a bore feature which projects through the mouthof the container into the interior thereof. The bore feature preferablycomprise a relatively rigid component, eg formed of PET or metal, andmay be integrally formed with the outer component or secured thereto. Ina particularly advantageous arrangement, the outer component is able torotate about the axis A relative to the bore feature. The outercomponent can thus be rotated, eg to fasten or release the closurewhilst the bore feature moves axially within the bore without rotatingtherein.

The bore feature may also be provided with an o-ring seal which engagesand seals with the interior of the container (or an upper surface of thecontainer lip). The bore feature and o-ring may be as described above.The o-ring may be in the form of a toroid of an elastomer located in agroove or gland on the outer surface of a bore feature. The o-ring mayalso be part of a resilient member moulded to fit the underside of thebore feature. The resilient sealing portion described above in relationto FIGS. 8-13 may include such a member. Thus, if the outer member shownin FIG. 9 projects into the bore of the container (rather than beingflat) and the resilient sealing portion follows the underside of thisfeature (again, rather than being flat) the resilient component may beformed with a portion which simulates the function of an o-ring toprovide a seal with the interior of the container.

In such embodiments employing an o-ring seal, the seal provided by thesandwiching of the flexible part of the inner component between theouter component and the upper surface of the container lip may no longerbe required. In this case, the outer component need not engage and/orcompress the flexible sealing component against the upper surface of thelip.

These further embodiments thus provide a closure for a container havinga circular opening defining an axis and a lip around said opening, theclosure comprising: an inner component having a collar portion forlocating about the exterior of the container beneath the lip of thecontainer and a sealing portion which, in use, extends from said collarportion over an upper surface of said lip; and an outer component forfitting over the inner component and interacting therewith forreleasably securing the collar portion thereof under said lip, theclosure having an o-ring seal for providing a seal between the closureand an upper or interior surface of the container.

The o-ring may be provided on a bore feature which, in use, projectsthrough the opening into the interior of the container, the bore featurebeing part of the inner and/or the outer component.

In a preferred arrangement, the collar portion may be relatively rigidand the sealing portion relatively flexible and the collar portion andthe sealing portion may be integrally formed with each other, eg by atwo-stage moulding process.

Preferably, the outer component has a skirt part for locating about thecollar portion of the inner component, the collar portion comprising aplurality of spaced apart radially moveable parts around itscircumference pivotally joined at their lower ends by a structureextending around the entire circumference of the collar portion.

The provision of an o-ring seal between the bore member and the internalsurface of the container body has a number of advantages:

-   -   It has relatively stable geometry when subject to        pressure-induced lifting of the closure (compared to that of a        seal provided on the upper surface of the container lip)    -   The degree of o-ring compression that is required is reduced        (compared to a seal on the upper surface of the container lip)        and the direction of the compression does not increase the        frictional engagement of the thread so the torque required to        compress the seal is reduced    -   Increased pressure within the container presses the o-ring seal        more tightly into the gap between the closure and the cap so        improving seal quality at higher pressures    -   Positive internal pressure also assists in releasing the seal by        applying an upward force against the underside of the closure so        helping overcome the frictional engagement between the o-ring        and the container wall.    -   The sealing surface are spaced from the container lip and thus        less susceptible to damage, eg during handling of the container.    -   The bore member allows the head space within the container to be        significantly reduced.    -   The o-ring (in an appropriately shaped gland) is able to provide        a seal irrespective of whether the internal pressure is higher        or lower than the external pressure so can be used both for        carbonated beverages and for vacuum packs. Other forms of seal        tend to be designed cater for one or the other application.

Using a bore feature which is formed separately from the cap alsoprovides the additional advantages:

-   -   Further reducing the torque required as the bore feature (and        hence the seal carried thereby) does not have to rotate with the        cap    -   Allows the bore feature to be formed of a different material, eg        a metal to reduce its gas permeability to almost zero    -   Makes it easier to separate the different components of the        closure for ease of recycling

As described, the o-ring is preferably a separate component, typicallyhaving a circular cross-section (although other cross-sectional shapesare possible) located within a recess extending around the circumferenceof a bore member. However, in other embodiments, the seal member mayhave other forms which simulate the sealing action of an o-ring and maybe integrally formed with a bore member, for example by using anover-moulded elastomer to form a virtual o-ring element.

An o-ring typically needs to be compressed by 10-30% to provide aneffective seal, whereas a compression gasket can require a much higherdegree of compression.

If the o-ring is located within a groove 4A as shown in FIG. 8, it ispreferably able to move axially within this groove in response toincreases or decreases in pressure within the container body. Thisenables the o-ring to respond to the increase in pressure and adopt ashape/position which is better able to withstand the pressure.

In each of the embodiments described, an o-ring is used to provide aseal between a closure and a container. The o-ring preferably sealsagainst an internal surface of the container but, in some embodiments,may seal against an upper surface thereof (particular at the point wherethis meets the internal surface). The sealing surface extends aroundeither the internal or the upper surface of the container.

The o-ring is located in a groove which has at least one side wall, thearrangement being such that, when the closure is installed on thecontainer, when subject to a pressure differential, the o-ring is movedand/or deformed so as to seal a gap between side wall and the container,the width of said gap being smaller than the cross-sectional width ofthe o-ring.

The closure may take a wide variety of forms including a cap-on-collarand other two-part arrangements such as those described as well as a onepiece closure. Preferably, the closure is arranged to be installedand/or released from the container by rotation around the axis passingthough the container opening.

An additional advantage of having a bore member which extends into theinterior of the container is that this occupies space at the upper endof the container that in a beverage container would usually otherwise beoccupied by a gas or provide a ‘headspace’, above the beverage.Reduction of the volume of this headspace, if it is occupied by air,reduces the amount of oxygen trapped within the container so increasingthe shelf-life of the beverage or, if it is filled with an inert gas,reduces the quantity of inert gas required.

In some cases, the cap or outer component may comprise an annularcomponent that has an upper portion that overlies the upper surface ofthe container lip so that it can provide a downward force on the lip, oron a seal member located between the lip and the cap, and a skirtportion which interacts with a collar or inner component (as describedabove) whereby the cap is secured to the container body.

The thread form used between the cap and the collar or inner and outercomponents (for a two-part closure) or between the cap and the container(for a one-piece closure) is preferably a multi-start thread form suchthat less than 360 degrees of rotation is required to install or removethe closure. With an eight-start threadform, the closure needs to berotated by only about 45 degrees to install or release the closure.

Intermittent threadforms and bayonet style threadforms such as thosedescribed in WO2006/000774 and WO2007/091068 may be used. In the case ofa bayonet theadform, the cap or outer component need not be movedaxially as the outer component is rotatably secured to the innercomponent. Similar threadforms may also be used with a one-piece closure(with the thread form provided on the container neck rather than on acollar).

For the avoidance of doubt, the verb “comprise” as used herein has itsnormal dictionary meaning, ie to denote non-exclusive inclusion. The useof the word “comprise” (or any of its derivatives) does not thereforeexclude the possibility of further features being included.

All of the features disclosed in this specification (including theaccompanying claims, and drawings) may be combined in any combination(other than combinations where at least some of the features aremutually exclusive).

Each feature disclosed in this specification (including the accompanyingclaims and drawings) may be replaced by alternative features serving thesame, equivalent or similar purpose, unless expressly stated otherwise.Thus, unless expressly stated otherwise, each feature disclosed is justan example of a generic series of equivalent or similar features.

The invention is also not restricted to the details of the embodimentsdescribed herein or to the specific combinations of features of theembodiments described. In particular, the invention includesarrangements as described in the claims with the addition of any one ormore features described or claimed herein including generalisations ofwhich those feature(s) are illustrative.

1.-37. (canceled)
 38. A closure for a container having a substantiallycircular opening defining an axis, the closure comprising: an innercomponent having a collar portion for locating about the exterior of thecontainer, an outer component for fitting over and/or around the innercomponent and interacting therewith so as to releasably secure the innercomponent to the container so the closure closes said opening, and abore member which, when the closure is secured to the container, extendsthrough said opening into the interior of the container, the closurehaving an o-ring sealing member mounted or mountable in or on an outersurface of the bore member so as to provide a seal with a sealingsurface of the container, when the closure is secured to the container,said sealing surface extending around an internal surface of thecontainer.
 39. A closure as claimed in claim 38 in which the bore memberis part of the inner and/or the outer component.
 40. A closure asclaimed in claim 38 in which the o-ring sealing member is located in agroove provided in the outer surface of the bore member, said groovecomprising at least two faces for constraining the cross-section of theo-ring sealing member.
 41. A closure as claimed in claim 39 in which thebore member is rotatable about said axis relative to the outercomponent.
 42. A closure as claimed in claim 38 in which the closurecomprises a cap having an upper portion and a skirt portion dependingfrom said upper portion.
 43. A closure as claimed in claim 42 in whichsaid upper portion is circular and, when the closure is secured to thecontainer, extends across the opening of the container.
 44. A closure asclaimed in claim 42 in which the outer component comprises an annularcomponent that has an upper portion that, in use, overlies an uppersurface of a lip of the container and a skirt portion that interactswith the inner component.
 45. A closure as claimed in claim 42 in whichthe outer component comprises a cap with an upper portion and a skirtportion depending therefrom and the inner component comprises a collar,the collar being arranged to engage beneath an outwardly projecting lipof the container and to fit between the container and the cap so as tosecure the cap to the container body.
 46. A closure as claimed in claim45 in which the inner component comprises a collar portion and a sealingportion which, in use, extends from said collar portion over an uppersurface of the lip and the outer component is arranged to fit over theinner component so as to releasably secure the collar portion beneath anoutwardly projecting lip of the container.
 47. A closure as claimed inclaim 38 in which the outer component is rotatably engageable with theinner component, said rotational engagement being provided by amulti-start thread form which requires rotation of less than 360 degreesbetween the outer component and the inner component to fasten and/orremove the closure from the container.
 48. A closure as claimed in claim46 in which the collar or collar portion comprises a ring portion, orother structure extending around the entire circumference of the collarportion, and a plurality of radially moveable portions spaced around thecircumference of the ring portion, the radially moveable parts beingjoined at their lower ends to said ring portion or other structure. 49.A closure as claimed in claim 48 in which the radially moveable portionsare resiliently biased towards said inner position.
 50. A closure asclaimed in claim 49 in which the outer component has a skirt portionwith a plurality of cams spaced around its internal circumference forurging and/or holding said radially moveable portions in an innerposition in which they are engaged beneath the lip of the containerbody.
 51. A closure as claimed in claim 38 in combination with acontainer adapted to be closed by said closure.